<style>
    .background-white{
    background-color:#2B2B2B;
    color:white;}
</style>

<div class="background-white">
    <form name="_xclick" action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_blank"
          onsubmit="return validateForm()">

        <input type="hidden" name="cmd" value="_xclick">

        <input type="hidden" name="business" value="paypal@vienlien247.com">

        <input type="hidden" name="currency_code" value="USD">

        <input type="hidden" name="item_name" value="v247">
        <select name="itemprice" class="inputbox" id="itemprice">
            <option value='25'>V247 $25.00 USD</option>
            <option value='50'>V247 $50.00 USD</option>
            <option value='100'>V247 $100.00 USD</option>
            <option value='200'>V247 $200.00 USD</option>
            <option value='300'>V247 $300.00 USD</option>
        </select>

        <input type="hidden" name="on1" value="So Phone nạp tiền vào">

        <input type="text" name="os1" maxlength="200" class="inputbox"
               placeholder="Số phone (ví dụ : 0123456789)...">

        <input type="hidden" id="amount" name="amount" value="">

        <input type="hidden" id="shipping" name="shipping" value="0">

        <input type="hidden" name="charset" value="utf-8">

        <input type="image" id="btnPaypal" onclick="return "
               src="https://www.paypalobjects.com/en_US/i/btn/btn_buynowCC_LG.gif"
               border="0"
               name="submit" alt="Make payments with PayPal - it's fast, free and secure!">

    </form>
</div>